1. Field of the Invention
The present invention relates generally to a method of fabricating a multilayer capacitor, and more particularly, to a method of fabricating a multilayer capacitor comprising improved steps of forming, laminating and applying pressure to a ceramic green sheet.
2. Description of the prior Art
In the heretofore well-known method of fabricating a multilayer capacitor, a ceramic green sheet mainly composed of dielectric ceramic is first formed on a supporting film by a doctor blade process. The ceramic green sheet formed is then stripped from the supporting film and Is further cut so as to have a predetermined area. An electrode paste for forming an inner electrode is printed on the surface of a ceramic mother green sheet obtained by cutting and then, a plurality of ceramic mother green sheets are laminated and heat pressed by applying pressure, to obtain a laminated body. Then the laminated body is cut into several respective laminated bodies of predetermined area for each multilayer capacitor is sintered, and is followed by the steps such as the step of providing an outer electrode, thereby to obtain a multilayer capacitor.
In the multilayer capacitor, a plurality of inner electrodes are laminated and separated by dielectric ceramics. Accordingly, the multilayer capacitor is small in size and large in capacity. However, a smaller-sized and larger-capacity capacitor is desired. In order to increase the size and capacity of the multilayer capacitor, dielectric ceramics having a high dielectric constant should be used. Alternatively, a thinner ceramic green sheet should be used.
When a thinner ceramic green sheet is used, however, lack of strength of the ceramic green sheet causes the ceramic green sheet to be, for example, torn, crumpled, or shifted position from the time when the ceramic green sheet is stripped from a supporting film to the time when it is laminated. As a result, a large-capacity capacitor as designed cannot be reliably obtained. Consequently, it is actually very difficult in terms of handling to fabricate a multilayer capacitor using ceramic green sheet having a thickness of 20 .mu.m or less.
On the other hand, Japanese Patent Laid-Open Gazette No 102216/1988, equivalent to co-pending Ser. No. 07/347,498 filed May 4, 1989, commonly assigned, discloses method of processing a ceramic green sheet for a multilayer capacitor in which cutting precision can be heightened even when a very thin ceramic green sheet is used. In the method disclosed in this prior art, a ceramic green sheet for a multilayer capacitor is first formed on the upper surface of a carrier film. Only the ceramic green sheet is then cut by a cuttIng head having a drawing portion with the ceramic green sheet being supported on the carrier film. The cut ceramic green sheet is drawn into the cutting head, to be taken out. More specifically, in this method, the ceramic green sheet is cut on the carrier film and then, the cut ceramic green sheet is stripped from the carrier film, thereby preventing the ceramic green sheet from being, for example, torn or crumpled. In this prior art, however, the steps after obtaining the ceramic green sheet out are not described except that a predetermined number of ceramic green sheets are laminated to obtain a laminated body, the laminated body obtained is diced into capacitors, and the laminated body cut is sintered.
Furthermore, the above described prior art discloses the step of drawing the cut ceramic green sheet out into the cutting head and holding the same therein, but fails to disclose the step of separating the ceramic green sheet which is already cut, from the cutting head.